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Journal of the American Mosquito Control Association Vol. 3, No. 2 



Department of Entomology, North Carolina State University, Box 7613, Raleigh, NC 27695-7613 

The maintenance of most mosquito species in 
the laboratory requires periodic feeding of blood 
to females. The expense and inconvenience of 
maintaining laboratory animals for this purpose 
has led to the development of methods for feed- 
ing preserved blood through various natural and 
artificial membrane materials (Tarshis 1958, 
Bailey et al. 1978, Wirtz and Rutledge 1980, 
Savage et al. 1980, Thomas et al. 1985). The 
resulting convenience and cost reduction can 
more than compensate for the reduced egg pro- 
duction reported by some of these workers, es- 
pecially in laboratories where mass rearing is 
done. In our mosquito rearing facility, where 
production demands are usually low, this tech- 
nique proved to be worthwhile. To decrease han- 
dling time, devices for holding and filling the 
membrane, and for maintaining a constant 
blood temperature were constructed. 

Initially, a coiled glass tube was inserted into 
the blood-filled condom, and 40°C tap water 
circulated through it. This device required prox- 
imity of hot and cold running water and, due to 
unpredictable changes in hot water temperature, 
needed constant adjustment. Aquarium heaters 
have been used to maintain the temperature of 
a water bath for a specialized membrane blood- 
feeding device described by Tarshis (1958), and 
for directly warming blood held in a condom (D. 
A. Dame, personal communication). In the latter 
case, use of the heater was discontinued because 
it frequently malfunctioned; however, we re- 
cently have obtained satisfactory results from 
an electric heater that was modified as described 

As a base for holding both the condom and 
the heater, four disks were cut from acrylic sheet 
(Lucite™, DuPont Co., Methacrylate Products 
Division, Wilmington, DE 19898) and laminated 
with methylene chloride to the configuration 
shown in Fig. 1. Three holes were drilled through 
the resulting stack: a 2.54 cm (1 in.) diam. hole 
through the center to hold the heater tube and 
two 5 mm (3/16 in.) diam. holes on opposite 
sides of the center hole for filling and draining 
the device. The resulting collar has a groove 
formed by the 6 x 36 mm diam. disc in which 

1 This is paper number 10890 of the Journal Series 
of the North Carolina Agricultural Research Service, 
Raleigh, NC 27695-7601. The use of trade names does 
not constitute endorsement of one product to the 
exclusion of others. 

the opening of the condom can be held by a 
rubber band. A 20 cm (8 in.), 50 watt, 110 VAC 
automatic aquarium heater (Fritz Pet Products, 
Div. of Fritz Chemical Co., Dallas, TX 75217) 
was modified as follows: The plastic screw- 
clamp assembly was removed and discarded al- 
lowing removal of the printed circuit board and 
heating element from the glass tube. The pilot 
light and resistor were removed and two 20 
gauge, insulated wires were soldered in their 
place. These wires were threaded through the 
same holes in the rubber plug as the AC power 
leads and wrapped to the AC cord for a distance 
of 1 m, at which point the remaining AC cord 
and plug were clipped off. The wires were 
threaded into a plastic electrical outlet box in 
which a 600 watt, 120 VAC incandescent dim- 
mer switch (Lutron Corp., Coopersburg, PA) 
and one miniature 120 VAC neon lamp (Radio 
Shack #272-707) were mounted. The 20 guage 
wires were connected to the neon lamp, and the 
power cord was wired to an additional 2 m of 
lamp cord with the dimmer switch interposed in 
one of the lines. 

The heater was then mounted in the plastic 
collar with silicone cement (General Electric 
Silicone Windshield and Glass Seal™) such that 
the top 2 cm of the glass tube projected above 
the top of the collar. An additional 3.6 cm diam. 
collar cut from a single thickness of 3 mm (Vsth 
in. nominally) acrylic sheet was cemented 1.5 
cm from the bottom tip of the tube to prevent 
the membrane from contacting the heated glass. 
Sixteen holes of 5 mm ( 3 /i6 in.) diam. were drilled 
around the periphery of this collar to allow blood 
to flow past it. 

A feeding port similar to that described by 
Bailey et al. (1978) was added to the top of each 
of our 30 x 30 x 30 cm aluminum screen cages 
by replacing the screen on half of the top with 
3 mm acrylic sheet. A 22 cm long by 3.8 cm 
diam. sleeve of mosquito netting material ex- 
tended into the cage from a 4.5 cm diam. hole 
in the sheet to support the membrane feeding 
device and prevent escape of mosquitoes. 

Pig blood was collected at a local slaughter 
house and sodium citrate (3.3 g in 25 ml water 
per liter of blood) was added to prevent coagu- 
lation. Since blood treated in this way deterio- 
rated in 2-5 days under refrigeration, all but a 2 
day supply was immediately frozen in 200 ml 
aliquots. Fresh blood was used as is, but our 
Aedes spp. fed poorly or not at all on blood that 

June 1987 

Operational and Scientific Notes 



Fig. 1. Diagram of blood heating device showing 
configuration of plastic collars and modifications to 

had been previously frozen. Adenosine 5' tri- 
phosphate sodium salt (Sigma Chemical Co. #A- 
3377), at a concentration of 2.5 mg/ml of thawed 
blood (Wirtz and Rutledge 1980), stimulated 
rapid and complete engorgement (Hosoi 1959). 

Prior to feeding mosquitoes, a natural mem- 
brane condom is rinsed in warm water and 
slipped over the heating device. The elastic 
string bonded to the opening of the condom is 
secured into the groove in the plastic collar with 
a rubber band. The dimensions of the device as 
given in Fig. 1 are most suitable for use with 
Kling-Tite Naturalamb™ condoms (Carter 
Products, Div. of Carter- Wallace, Inc., New 
York, NY 10153). Other brands tested were 
often irregular in shape, size and thickness. The 
basic design can be adapted for use with the 
collagen sausage casings described by Wirtz and 
Rutledge (1980). To fill the device, it is first 
placed in a stand fabricated from 3 mm acrylic 
sheet (Fig. 2). Blood is poured in through a small 
funnel set into one of the holes in the collar 
while the other hole acts as a vent. Filling the 
membrane to within 3 cm of the collar requires 
150 ml. The condom should not be filled to the 
top or blood will be forced out of the fill holes 
when it is placed into the feeding port. The holes 
can be stoppered with microvial corks if desired. 

The thermostat adjustment knob projecting 
from the top of the heater is used to set the 

Fig. 2. The membrane blood-feeding device with temperature control, stand and modified cage top. 


Journal of the American Mosquito Control Association Vol. 3 No. 

blood temperature. At the setting we use, the 
blood temperature oscillates between 37 and 
39°C as the thermostat cycles on and off. The 
pilot light indicates when the thermostat con- 
tacts are closed and current is reaching the 
heating element. This is useful for determining 
when the set temperature has been reached so 
that it may be adjusted if necessary. The dimmer 
switch is used to limit the temperature of the 
heating element; otherwise, blood will cake onto 
the surface of the glass tube near the element. 
The device was calibrated with a condom full of 
water and two thermistor probes inserted 
through the fill holes to monitor the temperature 
of the water and the glass surface next to the 
heating coil. Two settings were marked on the 
dimmer switch. The higher setting limits the 
temperature of the glass surface to ca. 55°C, and 
is used only in the initial heating of the blood. 
About 15 min is required to heat the blood from 
10 to 37°C. The lower setting is the lowest that 
will reliably activate the device when the ther- 
mostat contacts close, and is used to maintain 
the blood at the temperature set with the ther- 
mostat adjustment knob. 

After reaching the desired temperature, the 
device is inserted into the feeding port of a 
screen cage. When fresh blood is used, the upper 
collar rests on two 150 ml specimen cups such 
that only the lower two-thirds of the membrane 
are inserted, thereby preventing some mosqui- 
toes from engorging on serum after the cellular 
elements have settled. After use, the device is 
normally emptied and cleaned; however we have 
stored the device, filled with blood, at 2-5°C for 
up to 48 hr and reused it successfully. When not 
filled, the membrane is removed from the device, 
rinsed and then stored frozen. Individual mem- 
branes were used for up to six days of feeding. 

The species of mosquitoes successfully main- 
tained in our laboratory using this bloodfeeding 
technique are Aedes aegypti (L.), Ae. triseriatus 
(Say), Anopheles quadrimacuhtus Say, and Pso- 
rophora ferox (von Humboldt). We have suc- 
cessfully fed over 1,000 Aedes aegypti within 30 
minutes. Egg production data was accumulated 
only for Aedes aegypti, where five trials, each 
using ca. 150 females fed on fresh citrated pig 
blood, yielded a mean of 82.89 (±3.28 SD) eggs/ 
female in the first four days of oviposition. Five 

similar trials using a live rat as a host yielded a 
mean of 88.33 (±16.56 SD) eggs/female. The 
difference is not statistically significant. We 
cannot conclude however, that egg production is 
unaffected by membrane feeding, as the nutri- 
tional qualities of rat vs. pig blood are probably 
different. Pig blood has been shown to have a 
relatively high isoleucine concentration which 
enhances egg production (Lea et al. 1958). A 
comparison of previously frozen versus fresh pig 
blood has not been conducted. Thomas et al. 
(1985) reported a significant decrease in fecun- 
dity of Anopheles albimanus Wiedemann fe- 
males when fed on previously frozen versus fresh 
bovine blood. 

The use of this device at our facility has been 
more convenient than the use of laboratory an- 
imal hosts or a membrane device warmed in a 
water bath. The total cost for materials, which 
were all available locally, was ca. $30.00. 

We are grateful to Dr. R. G. Weber, Depart- 
ment of Entomology, University of Delaware, 
for valuable suggestions regarding design; to R. 
C. Axtell, C. Geden and M. Slaff for reviewing 
the manuscript; and to D. A. Kramer for pro- 
ducing the diagram. 


Bailey, D. L., D. A. Dame, W. L. Munroe and J. A. 
Thomas. 1978. Colony maintenance of Anopheles 
albimanus Wiedemann by feeding preserved blood 
through natural membrane. Mosq. News 38: 

Hosoi, T. 1959. Identification of blood components 
which induce gorging in the mosquito. J. Insect 
Physiol. 3:191-218. 

Lea, A. O., J. B. Dimond and D. M. DeLong. 1958. 
Some nutritional factors in egg production by Aedes 
aegypti. Proc. 10th Int. Congr. Entomol. 3:793-796. 

Savage, K. E., R. E. Lowe, D. L. Bailey and D. A. 
Dame. 1980. Mass rearing of Anopheles albimanus. 
Mosq. News 40:185-190. 

Tarshis, I. B. 1958. Feeding techniques for bloodsuck- 
ing arthropods. Proc. 10th Int. Congr. Entomol. 

Thomas, J. A., D. L. Bailey and D. A. Dame. 1985. 
Maintenance of Anopheles albimanus on frozen 
blood. J. Am. Mosq. Control Assoc. 1:538-540. 

Wirtz, R. A. and L. C. Rutledge. 1980. Reconstituted 
collagen sausage casings for the blood feeding of 
mosquitoes. Mosq. News 40:287-288.